Deleen was a Tsalmoth employed as a librarian in the Imperial Library in Adrilankha. As told in Dzur, Vlad enlisted Deleen's aid when researching the current state of the Jhereg Council while trying to figure out what The Left Hand of the Jhereg was up to in South Adrilankha.
Over the course of several days of digging through piles of newsletters and other records, and using sorcery to search for patterns of symbols in the documents, Deleen informed Vlad that:
- The Left Hand of the Jhereg did not interfere with the primary operations of the Jhereg Organization.
- The Empire kept an eye on the Left Hand, but only very rarely prosecuted any of their members.
- The Left Hand was very loosely organized, with little control over its members.
- Curithne had died of old age a year and a half prior. When asked who he was, Vlad explained that there was a "rumor", which he himself believed, that the old man had been Number One on the Jhereg Council for many years.
- No one had taken Curithne's position as number one yet.
- A power struggle was going on in the Jhereg, but not really a Jhereg war as such.
- The names of the highest-level Jhereg bosses vying for position were Poletra, Daifan (whom Vlad knew as The Demon), and Terion - and that the latter was rumored to have a mistress named Triesco in the Left Hand.
After Vlad felt he had learned enough, he thanked Deleen for his help. Deleen seemed surprised at the idea that Vlad might have wanted the information for a particular purpose, rather than just gathering it as an intellectual exercise.
After speaking to Vlad for the last time, Deleen seemed to forget that Vlad existed. He is, presumably, still employed as a Librarian.